

A342957


a(n) is the least k such that A342956(k) = n.


1



1, 2, 4, 15, 39, 87, 183, 951, 1255, 1527, 3063, 15335, 12279, 61431, 49143, 516047, 491495, 1703767, 1310695, 8257487, 3145719, 15728631, 12582903, 94371815, 50331639, 352321527, 335544295
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OFFSET

0,2


COMMENTS

a(n) exists for all n, as A342956(2^(2^k)) = k+1.
If 2^n = p+q where p and q are primes, then A342956(p*q) = n so a(n) <= p*q <= 2^(2*n2). Goldbach's conjecture implies such p and q exist for all n >= 2.


LINKS



EXAMPLE

a(3) = 15 because A342956(15) = 3 and this is the first appearance of the value 3 in A342956.


MAPLE

f:= proc(n) local t; numtheory:bigomega(add(t[1]*t[2], t=ifactors(n)[2])) end proc:
V:= Array(0..18): count:= 0:
for n from 0 while count < 19 do
v:= f(n):
if v <= 19 and V[v] = 0 then
count:= count+1; V[v]:= n
fi
od:
convert(V, list);


MATHEMATICA

Table[n=0; While[PrimeOmega[Plus@@Times@@@FactorInteger@++n]!=k]; n, {k, 0, 14}] (* Giorgos Kalogeropoulos, Aug 20 2021 *)


CROSSREFS



KEYWORD

nonn,more


AUTHOR



EXTENSIONS



STATUS

approved



